Ion exchange resins have been prepared by copolymerization of various ionic monomers and crosslinking monomers as described, for example, in U.S. Pat. No. 7,683,100 (Rasmussen et al.), U.S. Pat. No. 7,674,835 (Rasmussen et al.), U.S. Pat. No. 7,674,836 (Rasmussen et al.), and U.S. Pat. No. 7,098,253 (Rasmussen et al.). Some ion exchange resins have been used for purification and/or separation of biomolecules such as proteins. To be useful in large scale purification and/or separation processes, ion exchange resins with relatively high binding capacity and sufficient rigidity to withstand pressure-flow requirements encountered in large diameter chromatographic columns are often desired. Preparing ion exchange resins with this combination of suitable rigidity and binding capacity has been a challenge in the industry.